drm/xe/vf: Stop applying save-restore MMIOs if VF

Currently we are blocking processing of all save-restore rules
by the VFs inside the xe_rtp_process_to_sr() function, but we
want to unblock that to allow processing of the LRC WA rules.

To avoid hitting WARNs about reading an inaccessible registers by
the VFs, stop applying save-restore MMIOs action if VF, without
relying that SR list will be always empty for the VF.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250303173522.1822-5-michal.wajdeczko@intel.com